Regarding a rechargeable cell such as a capacitor or a secondary battery, a large number of cells of this type is often used being series-connected. In such a case, if the voltage is different among the cells, a problem occurs that lifetimes of the cells shorten due to concentration of voltage in a specific cell. The more cells are series-connected, the more noticeable this problem is. Therefore, in the use of rechargeable cells with being series-connected, the voltages of the cells are required to undergo balance correcting (to be balanced). The description below shows conventional arts for performing the voltage-balance correcting.
—Voltage-Balance Correcting Circuit—
As a circuit for balance correcting the voltages of cells (voltage-balance correcting circuit), an inductor coupling type and a transformer coupling type are known (see Patent document 1 to 3, for example). Conventional examples 1 to 3 will be given below as a conventional voltage-balance correcting circuit.